物理化学学报 >> 1988, Vol. 4 >> Issue (04): 361-365.doi: 10.3866/PKU.WHXB19880407

研究论文 上一篇    下一篇

CO氢化合成乙醇反应的过渡应答研究——Ⅱ. 改性Rh/Al2O3催化剂上的反应动力学研究

陆云; 刘旦初; 郑绳安   

  1. 复旦大学化学系
  • 收稿日期:1986-10-11 修回日期:1987-04-28 发布日期:1988-08-15
  • 通讯作者: 郑绳安

STUDIES ON THE SYNTHESIS OF ETHANOL FROM CO HYDROGENATION WITH THE TRANSIENT RESPONSE TECHNIQUE Ⅱ. THE REACTION MECHANISM OVER MODIFIED Rh/Al2O3 CATALYSTS

Lu Yun; Liu Danchu; Zheng Shengan   

  1. Department of Chemistry; University of Fudan; Shanghai
  • Received:1986-10-11 Revised:1987-04-28 Published:1988-08-15
  • Contact: Zheng Shengan

摘要: 本文用过渡应答技术研究CO在改性Rh/Al_2O_3催化剂上常压氢化合成乙醇的表面反应机理。结果表明: 1. 在Rh/Al_2O_3催化剂中添加K元素能显著地增加合成乙醇反应的活性和选择性; 2. 乙醇的生成取决于表面上相邻两个含氧中间体的密度而与气相中的H_2或CO浓度无关。反应倾向于ANDERSON的缩聚机理。
在此反应机理的基础上, 由应答曲线的数据, 根据MARQUARDT非线性优化技术以及RUNG-KUTTA-GILL数值积分法计算了所有基元步骤的反应速率常数。

Abstract: In the present paper the surface reaction mechanism with that the CO hydrogenation will proceed to ethanol is investigated by the transient response method using a quadrupole mass spectrometer under atmospheric CO-H_2 over Rh/Al_2O_3 and K doped Rh/Al_2O_3 catalysts.
According to the experimental results, it is found that: 1. the presence of K causes a marked increase in the steadystate rate and selectivity for ethanol synthesis; 2. the formation of ethanol depends on the surface adjacent intermediates and is independent of the concentration of CO or H_2 in the gas phase, i.e. the results favor the condensation mechanism to the insertion mechanism.
A mechanism of ethanol synthesis on the modified Rh/Al_2O_3 has been proposed and a set of rate constants of all elementary steps are calculated by Marquardt nonlinear optimization technique and Rung-Kutta-Gill numerical value integration method.